Conor McGregor is a professional mixed martial artist from Dublin, Ireland. He currently fights in the lightweight division in which he is ranked #9 and is based out of Straight Blast Gym in his hometown. He trains with many notable Irish fighters such as John Michael Sheil, Peter Queally, Artem Lobov, Cathal Pendred, Chris Fields and Aisling Daly. Conor is a Brown Belt in Brazilian Jiu-Jitsu. He also trains in both Dublin and Iceland with fellow UFC fighter and current 170-pound prospect Gunnar "Gunni" Nelson.

McGregor made his MMA debut in an amateur fight against Kieran Campbell on February 17, 2007 at a local Irish promotion and won by first round TKO. In 2008, he went pro and started training under the founder and head coach of SBG Ireland, John Kavanaugh. Conor's first pro fight was against debutante Gary Morris and he finished the fight in the second round. Less than two months later, Conor won his second fight against Mo Taylor via first round TKO and advanced to 2-0 in his professional career. Then, he decided to move to the Featherweight division and fought Artemij Sitenkov who handed McGregor his first MMA loss.

Conor's next fight was booked against Stephen Bailey, a fight he won in the first round. After that fight, McGregor contemplated leaving MMA for a different career path but his mother with the help of his mentor and coach John Kavanaugh, reactivated his hunger to become World Champion and to continue to pursue MMA because they knew he was destined for greatness. About two years later. McGregor came back to fight Conor Dillon on October 9, 2010 and won in the first round by corner stoppage.

On November 27th, he went back up to lightweight to fight undefeated Irish prospect and future fellow UFC fighter Joe Duffy and unfortunately, Conor was given his second career loss, once again by submission in the first round. After the tough loss, he would go on to KO/TKO his next six opponents (Hugh Brady, Mike Wood, Paddy Doherty, Artur Sowinski, Aron Jahnsen and Steve O'Keefe) and looked very impressive doing so, earning himself a Cage Warriors Featherweight Championship fight against Dave Hill at Cage Warriors 47 on June 2, 2012. McGregor once again looked fantastic in the fight but unlike all his other wins, he finished the fight by rear-naked choke in the second round against a very tough opponent who had never been finished. He jumped into the crowd after the fight and was embraced by many of his hometown fans similar to Jose Aldo at UFC 142 in Rio.

After winning the Featherweight belt, Conor was scheduled to face Jim Alers on the 31st of December, 2012 at Cage Warriors 51 in Dublin but Alers had to pull out citing a hand injury. McGregor instead faced Ivan Buchinger for the Cage Warriors Lightweight Championship. He put on an extremely dominating performance showing off all facets of his mixed martial arts skills finishing Buchinger by KO at 3:40 of round 1. "The Notorious" Conor McGregor became the first European MMA fighter to hold titles to two divisions at the same time.

In February 2013, he met Dana White and was signed by the UFC. McGregor would face fellow featherweight prospect Marcus Brimage on the preliminary card of  UFC on FUEL TV 9 in Stockholm, Sweden for his UFC debut. McGregor would make an impressive statement with his debut knocking Brimage out in the first round to earn himself Knockout of the Night honors in his debut. His next test would be against future UFC Featherweight Champion Max Holloway when they squared off at UFC Fight Night 26. Even though McGregor tore his ACL during the fight he would go on to win a unanimous decision showing his wrestling skills by taking his opponent down and controlling him with surprising ease.

After a nearly one-year layoff resulting from the injury, McGregor would come back to face Diego Brandao as the main event of UFC Fight Night 46. He would make it 3 in a row in the UFC by finishing Brandao with strikes in the first round. McGregor then faced Dustin Poirier on September 27, 2014, at UFC 178. He won via TKO in the first round. The win also earned McGregor his second Performance of the Night bonus award. McGregor would then face Dennis Siver on January 18, 2015, at UFC Fight Night 59 and for the third straight time, he would win by TKO and also earn the Performance of the Night bonus. He was then slated to face Jose Aldo at UFC 189, but Aldo withdrew with rib injuries. Two weeks before the fight he instead opted to face Chad Mendes for the UFC Interim Featherweight Championship. He knocked Mendes out in the final seconds of round 2 after going through one of the toughest fights of his career and once again earning himself a Performance bonus. The gate broke the record for an MMA event in the United States at $7,200,000. You may note that after the fight he was approached by Frankie Edgar, who he most likely would have faced if he hadn't taken his hiatus from MMA from 2016-2018.

Before fighting Mendes at UFC 189, Conor was chosen to coach the European team for The Ultimate Fighter Season 22. His team succeeded in wiping out the American team coached by former UFC Bantamweight contender and WEC Featherweight Champion Urijah Faber. McGregor's teammate and prodigy Artem Lobov was scheduled to face Saul Rogers in the TUF 22 finale. However, due to visa issues Saul was forced to pull out and was replaced by Ryan Hall, who won the fight by UD, much to McGregor's dismay.

On December 12, 2015, McGregor finally faced UFC Featherweight Champion Jose Aldo at UFC 194. The event sold around 1.2 million PPVs which would make it the second most in UFC history at the time only trailing behind the legendary UFC 100. Before the fight, the majority of experts were picking Aldo considering he was on a seven-year long title reign in the WEC and UFC and on an 18 fight win streak, looking more impressive each and every fight. The buildup to the fight included a lot of trash talking from McGregor and many fans started to think that his mind games were what were winning him the fights before even stepping into the octagon. However, in the fight, McGregor came out very calm and waited for Aldo to lunge forward before sneaking in an explosive left hook and knocking him out 13 seconds into the first round to earn the Undisputed UFC Featherweight belt, shocking the world and making him the first Irish-born UFC champion. The finish was the fastest ever in a UFC title fight and not surprisingly led to Conor's fifth straight Performance of the Night bonus, a UFC record.

After capturing gold at 145 lbs, McGregor wanted to move up to 155 lbs and challenge Rafael Dos Anjos for the UFC Lightweight Championship at UFC 196 but RDA had to withdraw after breaking his foot. Afterwards, many names were thrown around as Conor's next possible opponent, but the fight that was eventually booked was Conor McGregor vs Nate Diaz at UFC 196 and at Welterweight (170 lbs)! Less than four months after fighting at 145 lbs, Conor fought Nate Diaz at 170 lbs and was handed his first UFC loss when Diaz made him tap due to a rear naked choke in the end of the second round. The fight earned Fight of the Night honors and the event surpassed McGregor's previous PPV record with around 1.3 million buys.

A rematch with Diaz was booked for UFC 200 but McGregor was taken off the event after failing to meet the media obligations prior to the fight. Therefore, the rematch was rescheduled for UFC 202 on August 20, 2016. The fight was extremely entertaining with both fighters having their moments in the fight but after five rounds, McGregor was announced the winner by Majority decision. Once again, the fight received Fight of the Night honors and broke the UFC PPV record with over 1.6 million buys this time!

Conor was then set to face UFC Lightweight Champion Eddie Alvarez on November 12, 2016 at UFC 205, a card Dana White referred to as the "biggest fight card in the company's history" and the first UFC event hosted in New York City as well as the first UFC event in the state of New York since UFC 7. In the main event, Conor put on one of his best if not the best performance of his MMA career when he absolutely outclassed the Lightweight Champion Eddie Alvarez en route to a second round TKO. McGregor also made history by becoming the first UFC fighter to hold belts in two divisions simultaneously (Featherweight and Lightweight). A couple weeks later, he was stripped of the Featherweight title due to inactivity and eventually the Lightweight title as well, after deciding to take a step away from the octagon and focus on the birth of his first child. After UFC 223, McGregor's Lightweight belt was taken away due to inactivity and Khabib Nurmagomedov was crowned the new UFC Lightweight Champion after defeating Al Iaquinta by unanimous decision.

McGregor would go on to box undefeated boxing superstar Floyd Mayweather Jr, losing the bout by tenth round TKO. The fight sold around 4.3 million PPVs making it the second most in history only behind Mayweather vs. Pacquiao.

In August 2018, Conor announced that he would return to the octagon to fight Khabib Nurmagomedov for the UFC Lightweight Championship on October 6 at UFC 229. Nurmagomedov bested McGregor in the fourth round, submitting him with a neck crank to retain his title. After the fight an altercation occurred in which McGregor was hit in the back of the head by an associate of Nurmagomedov. The highly anticipated fight at the T-Mobile Arena in Las Vegas lived up to financial expectations, selling over 2 million pay-per-view buys according to UFC President Dana White, breaking the previous UFC record set by UFC 202.

McGregor would announce his retirement and step away from the octagon for over a year before returning to fight at 170 lbs against UFC veteran Donald "Cowboy" Cerrone. He would win by TKO 40 seconds into the first round earning him another Performance of the Night bonus and making him the first UFC fighter to hold finishes at Featherweight, Lightweight, and Welterweight.

About a year later, McGregor fought Dustin Poirier in a rematch 6 years in the making at UFC 257 on January 23, 2021, the first main event to have limited attendance of fans since early 2020. McGregor looked great in the first round and was winning the fight, but Poirier's calf kicks started to take a toll on McGregor and eventually wore him down and led to Poirier avenging his previous loss to Conor by defeating him via TKO in the 2nd round and setting their record to 1-1.

McGregor and Dustin Poirier faced off in their much-anticipated trilogy fight on July 10th, 2021 at UFC 264. The fight sold 1.8 million PPVs, the second most in UFC history only behind UFC 229. Throughout the first round, Dustin looked like the better fighter and was winning most of the exchanges, then with just a few seconds left in the round, Conor stepped back and rolled his ankle, it looked very gruesome, like Anderson Silva's against Chris Weidman or Weidman's against Uriah Hall. The fight was stopped after one round because McGregor was deemed unable to continue due to a broken tibia and Dustin Poirier won the fight and therefore, the trilogy. Conor stated that he had stress fractures in his ankle before the fight, releasing photo proof and claiming that the fight was in jeopardy of being canceled due to his injury.